The Electronic Communications Privacy Act, which governs this area, was passed in 1986 before the World Wide Web took hold. Critics point to many anomalies in the law, including the way it treats email stored on remote computers -- the Cloud -- as less private than email stored on a home computer. But in 2010, a federal court found that the government needs a court order to look at email in certain cases.

"So what the IRS believes today is a little less clear," says Purdue computer science professor Christopher Clifton. Clifton says much of the issue revolves around our expectations of privacy. If we expect something is private, it stands a greater chance of being protected from unreasonable searches by the Fourth Amendment of the Constitution.